Graff desaturation

Post a reply


This question is a means of preventing automated form submissions by spambots.
Smilies
:D :) ;) :( :o :shock: :? 8-) :lol: :x :P :oops: :cry: :evil: :twisted: :roll: :!: :?: :idea: :arrow: :| :mrgreen: :geek: :ugeek:

BBCode is ON
[img] is ON
[flash] is OFF
[url] is ON
Smilies are ON

Topic review
   

Expand view Topic review: Graff desaturation

Re: Graff desaturation

Post by Creator » Tue Jan 26, 2010, 16:36

Starting from the version 1.0.30d we have corrected the Desaturate function. Now it produces the same result as in Adobe Photoshop. Basically this function, now uses the Hue/Saturation functionality, i.e C = [Min(R, G, B) + Max(R, G, B)] / 2.
To achive old result, i.e. C = [R + G + B] / 3, please use function Black & White with default settings.

Re: Graff desaturation

Post by Creator » Tue Jan 26, 2010, 12:39

Maybe it will be better example:
color_table_org.jpg
color_table_org.jpg (17.78 KiB) Viewed 11736 times

color_table_4.gif
color_table_4.gif (72.81 KiB) Viewed 11736 times

Re: Graff desaturation

Post by Creator » Tue Jan 26, 2010, 02:39

The difference can be illustrated here:
face_org_3.jpg
Original Photo
face_org_3.jpg (8.72 KiB) Viewed 11741 times
face_bw_3.gif
Desaturated Photo
face_bw_3.gif (71.81 KiB) Viewed 11741 times

Re: Graff desaturation

Post by Administrator » Tue Oct 13, 2009, 23:20

Photoshop uses the following approach. In the gray value of the pixel should the luminance be written. It is calculatd as average sum of the maximal and minimal color channel values.

Re: Graff desaturation

Post by Creator » Tue Oct 13, 2009, 17:16

Currently we use the following desaturation algorithm: C = (R + G + B) / 3.
Before committing a bug, I suggest to discuss desaturation here.

Graff desaturation

Post by Bar Welt » Tue Oct 13, 2009, 14:37

Hallo. I use Graff 1.0.24, and it looks like the desaturation algorithm performs not properly. I just compared the desaturated image with the same image after the desaturation in GIMP. Should I commit the bug report on that ?

Top